Clamping device for scaffolding



Aug. 29, 1961 c. F GROVER ETAL 2,997,767

CLAMPING DEVICE FOR SCAFFOLDING Original Filed Jan. '7. 1957 29 Hi 25a i:ll

INVENTORS.

Charles E Grover John A. B. Starr T HE IR A TTORI VE Y5 United States 12,997,767 CLAMPIN G DEVICE FOR SCAFFOLDIN G Charles F. Grover and JohnA. B. Starr, Greenville, Pa., assignors to R. D. Werner 'Co., Inc.,Greenville, Pa.,

a corporation of Pennsylvania Original application Jan. 7, 1957, Ser.No. 632,916, now Patent No. 2,917,129, dated Dec. 15, 1959. Divided andthis application Sept. 25, 1959, Ser. No. 842,445

'3 Claims. (Cl. 24-235) This invention relates to a clamping device, andmore particularly to a detachable clamping device for use in scaffoldingconstructions.

There has been an urgent need for relatively inexpensive, safe andpractical scaffold equipment, such as may be used for repairing,cleaning, renovating and adding installations or equipment to buildingconstructions. An important feature in scaffold equipment involves theease in which the scaffold construction may be safely erected into arigid structure and may be quickly disassembled for mobility. Therefore,it is important to have quickacting and easily engageable clampingdevices which will rigidly maintain the scaffolding structure in anassembled r upright position, and further, which are easily releasablefor quick disassembly of the structure. A further requirement of suchclamping devices is that they should be constructed in such a manner sothat they are, in effect, self-locking and will not inadvertently becomedisengaged during use.

It thus has been an object of our invention to provide a solution to theproblem of quickly releasable clamping devices for scaffoldingconstruction;

Another object of our invention has been to devise a new and improvedtype of clamping device for scaffolding construction which may besnapped-in-place without manually activating its latching mechanism;

A further object of our invention has been to provide an improvedclamping device for scaffolding which cannot be disengaged from itsclamped member without first manually activating its latching deviceindependently of the clamped-on member;

These and other objects of our invention will appear to those skilled inthe art from the following disclosure and accompanying drawings inwhich:

FIGURE 1 is a greatly enlarged side fragment through a clamp or snapfinger means and an associated hollow rail or cross member that isengaged thereby; in this figure, the full lines illustrate the clampfinger means in a down, holding or latching position upon the crossmember; the dot and dash lines illustrate the clamp finger means in itsupper, released, non-engaging or non-latching position with respect tothe cross member; and

FIGURE 2 is a top fragmental segment on the same scale as FIGURE 1 andtaken at right angles thereto.

Referring now to the drawings, a hollow tubular member 23, such as asupport body, swing frame or side member of a scaffolding structure, hasa frame lock or clamp means 26 connected thereto. The clamp means is ofa snap-on downwardly over-latching and an upwardly oifunlatching type.Cruciform end portions 26e having arcuate outer portions to conform withthe inner diameter of the hollow tubular member 23, receive the endportions of the members 23 in a telescoping engagement as shown in thedrawings. Each clamp 26 has an open, member-receiving bottom mouth orslot, a central slot or groove 26a, and an enlarged nose slot or groove26b. The slots 26a and 26b, in effect, bifurcate a major longitudinalportion of the clamp means and provide an opening to operatively receivea clamping or latch finger element 27. The clamping finger member 27 ispivotally mounted on a cross-extending pivot pin 28 in the nose of theclamp 26.

Patent 0 A resilient, double-torsion spring 29 is carried on the pin 28on opposite sides of the finger 27. The spring has a loop portion 29aover the finger 27 and has a pair of tension abutment feet portions 2%(see FIGURE 1) to provide the finger with a snap-latching or engagingaction. The feet portions 29b abut a lower jaw 26d forming one end ofthe slot 26b to resiliently hold or urge finger 27 towards its downposition (as represented by the full lines of FIGURE 1).

The clamp finger 27 is adapted to move within a supplementary back-slotor groove 260 of a guideway type. For this purpose, arearwardly-projecting back stop or control lug portion 270 is adapted tomove along the guideway 26c and between end abutment shoulders or stopportions a and b (see FIGURE 1). To release the latch finger 27, it isonly necessary to manually push-up its back end portion against thetension of spring 29. The clamp 26 is shown overlying and clamped inoperable engagement with a tubular member 14d, such as a transversemember, cross tie, or other frame member of a scaffolding construction.The construction of the spring acting clamp 26 permits a quick and easyengagement with the member 14d, either by moving the member 14d upwardlyWithin the clamp, or by applying the clamp 26 downwardly against themember 14d. In either case, the clamp is applied without exerting directmanual movement on the finger 27 (since the member 14d will push thelatch finger 27 upwardly against the action of the spring 29 and allowthe member to be inserted within the clamping jaws), as the clamp isapplied downwardly over and upon the member 14d. However, it is notedthat once the member 14d is positioned within the clamp it is releasablylocked in position by the spring-tensioned latching finger snapping backto its normal position (see FIGURE 1), and it cannot be removedtherefrom merely by pulling it apart, since an outward pull between theclamp 26 and the member 14d will tend to cause a gripping action on themember 14d, due to the curvature of the latching finger 27. The clamp 26may easily be removed from the member 14d merely by manually retractingthe finger 27 upwardly in the clamps 26 against the tension of spring29.

This is a divisional application of our application Serial No. 632,916,filed January 7, 1957, now Patent No. 2,917,- 129 and entitled HighClearance Scaffold.

What we claim is:

1. In a snap-on clamping device adapted to project from a swing framemember to detachably engage over a second frame member, a nose part ofunitary construction having a backWardly-projecting mounting portion forsecuring it on the first frame member to project forwardly therefrom,said nose part defining a forwardlyprojecting open-mouth clamp ofsubstantially arcuateshape for movement with the swing frame membertransversely on and ofi the second frame member, said clamp beingbifurcated forwardly thereof by an intermediate slotted portiontherealong that is open transversely thereof, said intermediate slottedportion having an enlarged diameter slotted portion adjacent a forwardend portion of said clamp, a substantially arcuate-shaped open-mouthlatching finger part, a pivot pin projecting through a forward endportion of said latching finger part across said enlarged diameterslotted portion and being secured at its ends within said clamp, saidpivot pin operatively positioning said latching finger part within saidslotted portions of said clamp with its open-mouth facing transverselyin the same direction as the open-mouth of said clamp for relativeswinging movement along said intermediate slotted portion between anunlatching position substantially within said clamp and a latchingposition in which its back end portion projects transversely beyond theback end portion of said clamp, the back end portion of said finger partwhen it is in its latching position engaging the second frame memberbeyond a side thereof that is substantially diametrically-opposite theengagement of the forward end portion of said clamp to securely hold thesecond frame member in a latched relation; and spring means mounted onsaid pivot pin, secured to the forward end portion of said clamp, andoperatively engaging the forward end portion of said finger part toresiliently urge the back end portion of said finger part out wardlybeyond said clamp into and resiliently retain it in a latching positionwith the second frame member.

2. A clamping device as defined in claim 1 wherein, said intermediateslotted portion of said clamp has an inset-slotted portion extendingarcuately-backwardly within said clamp and defining a guideway and stoplimit means spaced transversely within said clamp, and said finger parthas a backwardly-projecting lug positioned for movement along saidinset-slotted portion to guide said finger part between said stop limitmeans in its relative swinging movement and limit the maximum extent ofsuch movement for controlling the maximum swing of said finger partbetween its latching and unlatching positions within said clamp.

3. In a snap-011 clamping device to project from a swing frame member ofa scaffolding to detachably engage over a second frame member, a nosepart of unitary construction having a backwardly-projecting mountingportion for securing it on the first frame member to project forwardlytherefrom, said nose part defining a forwardly-projecting open-mouthclamp of substantially arcuate shape for movement transversely on andoff the second frame member, said clamp being bifurcated forwardlythereof by an intermediate slotted portion therealong that is opentransversely thereof, said intermediate slotted portion having anenlarged diameter slotted portion open to a front end portion of saidclamp, a substantially arcuate-shaped open-mouth latching finger partpositioned within and along said slotted portions of said clamp, a pivotpin extending through a front end portion of said finger part at saidenlarged diameter slotted portion and being secured at its ends withinthe front end portion of said clamp, said pivot pin pivotally mountingthe front end portion of said finger part for movement along saidintermediate slotted portion from an unlatching position therewithinwherein the back end portion of said finger part is substantially fullywithin said intermediate sloted portion to a latching position whereinthe back end portion of said finger part extends transversely from andin a cooperating latching position with said clamp and engages thesecond frame member beyond a side thereof that is substantiallydiametrically-opposite the engagement of the forward end portion of saidclamp to securely hold the second frame member in a latched relation,spring means projecting over the front end portion of said finger partand having side coil portions positioned about said pivot pin onopposite sides of said finger part and engaging said enlarged slottedportion to substantially center said finger part in its pivotedrelationship therewithin at the forward end portion of said clamp, saidspring means being secured to said clamp for resiliently urging saidfinger part to its cooperating latching position with said clamp, saidclamp having an inset arcuately-shaped slotted portion within saidintermediate slotted portion at its back end portion defining a guideslot and stop limit means at each end of said guide slot spacedtransversely within said clamp, and said finger part having a back guidelug operatively positioned for guided movement within said inset slottedportion and adapted to engage said stop means for limiting the swingingmovement of said finger part between its defined unlatching and latchingpositions.

References Cited in the file of this patent UNITED STATES PATENTS784,927 Cn'sler Mar. 14, 1905 795,966 George Aug. 1, 1905 1,128,719Poppenhusen Feb. 16, 1915 1,287,459 Schroeder Dec. 10, 1918 2,624,611Knapp Jan. 6, 1953 2,677,575 Phillips May 4, 1954 2,873,995 Turner Feb.17, 1959 FOREIGN PATENTS 134,296 Sweden Jan. 22, 1952

